The invention is based on an apparatus for avoiding wheel locking during braking and to limit drive slip at the driven wheels of a vehicle. Such an apparatus is already known (German Offenlegungsschrift 32 15 739). For limiting drive slip or for traction control, this apparatus has an electrically controlled 3/2-way valve in the master brake line, which in the traction control mode connects not a master brake cylinder, but instead a pressure reservoir, with at least one wheel brake. The pressure of the pressure fluid contained in the reservoir can thus act on the wheel brake, which is triggered by means of a pressure control valve assembly. If there is inadequate pressure in the reservoir, which is detected by means of a pressure switch, the pump, which has one pumping direction, is switched on. Via a pressure-controlled switchover valve, the pump, draws pressure fluid from the pressure fluid supply container of the master brake cylinder and pumps the pressure fluid to the pressure reservoir. A check valve connected parallel to the 3/2-way valve and having a pressure limiting spring is also provided, to protect the wheel brake, pressure control valve assembly, 3/2-way valve and pump from overloading. The known apparatus is not only relatively expensively embodied, but because the valves are connected serially between the master brake cylinder of the wheel brakes it has limited functional reliability.